diff options
| author | Ben Hutchings <bhutchings@solarflare.com> | 2012-02-21 02:57:33 +0000 |
|---|---|---|
| committer | Ben Hutchings <bhutchings@solarflare.com> | 2012-02-22 20:48:08 +0000 |
| commit | 01cb543db8a2d2dbcea5f357365ce1327ac46193 (patch) | |
| tree | 34f19534fcc79f1e2616424fa26fda2851918335 | |
| parent | c3cb2a874122889c036934294dbbb8ad82f53060 (diff) | |
sfc: Correct validation of peer_page_count in efx_vfdi_set_status_page()
efx_vfdi_set_status_page() validates the peer page count by
calculating the size of a request containing that many addresses and
comparing that with the maximum valid request size (4KB). The
calculation involves a multiplication that may overflow on a 32-bit
system.
We use kcalloc() to allocate memory to store the addresses; that also
does a multiplication and it does check for integer overflow, so any
values larger than 0x1fffffff will be rejected. However, values in
the range [0x1fffffffc, 0x1fffffff] pass boh tests and result in an
attempt to allocate nearly 4GB on the heap. This should be rejected
rather quickly as it's obviously impossible on a 32-bit system, and
indeed the maximum possible heap allocation is 32MB. Still, let's
make absolutely sure by fixing the initial validation.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
| -rw-r--r-- | drivers/net/ethernet/sfc/siena_sriov.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/net/ethernet/sfc/siena_sriov.c b/drivers/net/ethernet/sfc/siena_sriov.c index 5c6839ec3a8..80976e84eee 100644 --- a/drivers/net/ethernet/sfc/siena_sriov.c +++ b/drivers/net/ethernet/sfc/siena_sriov.c @@ -796,12 +796,13 @@ static int efx_vfdi_set_status_page(struct efx_vf *vf) { struct efx_nic *efx = vf->efx; struct vfdi_req *req = vf->buf.addr; - unsigned int page_count; + u64 page_count = req->u.set_status_page.peer_page_count; + u64 max_page_count = + (EFX_PAGE_SIZE - + offsetof(struct vfdi_req, u.set_status_page.peer_page_addr[0])) + / sizeof(req->u.set_status_page.peer_page_addr[0]); - page_count = req->u.set_status_page.peer_page_count; - if (!req->u.set_status_page.dma_addr || EFX_PAGE_SIZE < - offsetof(struct vfdi_req, - u.set_status_page.peer_page_addr[page_count])) { + if (!req->u.set_status_page.dma_addr || page_count > max_page_count) { if (net_ratelimit()) netif_err(efx, hw, efx->net_dev, "ERROR: Invalid SET_STATUS_PAGE from %s\n", |